Windpower Engineering & Development
A floating turbine that avoids migratory bird patterns, NIMBY activists, and state jurisdictions, according to American Offshore Energy. The Pennsylvania-based company says its vertical-axis wind turbine (VAWT) uses tension and compression design principles, which allow a stiff, lightweight, fixed-wing-composite structure that can be scaled to huge sizes, and could one day bring consistent renewable energy to coastal cities.
In a white paper, the company outlines many reasons VAWTs should dominate offshore windpower production. For one, the company sees abandoned shipyards becoming manufacturing centers for the country’s best energy endeavor. American Offshore Energy suggests these other reasons as well:
Demand – About 70% of electricity demand is near coasts and the Great Lakes. Meanwhile, the nation’s best wind resources are only 30 miles offshore. In addition, offshore wind is located far closer to existing energy infrastructure than many land-based projects.
Wind resource – While VAWTs are noted for being less efficient than their horizontal-axis cousins, the Class 6 winds offshore, which have twice the energy of the best continental winds, can bridge the gap. Winds at sea blow more consistently, too.
Air bearings – Bearings with the capacity and speed to support a large swept area at the perimeter are only recently available. American Offshore Energy says these air bearings for wind turbines are a disruptive technology.
The air bearing in the base work this way: The base employs three floats each with a set of bearings to provide a kinematic support, that is three points will always define a plane for the base rotor no matter how the float structure may distort or pitch with waves.
Flotation – Horizontal-axis turbines must be pointed into the wind, a necessity that requires huge platforms or economically impractical floats. VAWTs, on the other hand, are not sensitive to wind direction.
Out of sight – A 200-ft. tall turbine would be below the horizon 30 miles offshore. This reduces the arguments and legal bickering that increases costs of wind farms. What’s more, there are few bats and birds 30 miles offshore.
No gearboxes – With thousands of precision pieces, gearbox failure is all but inevitable. In addition, the cost of offshore wind maintenance is three times that for on-shore turbines. Also, because there is no gearbox, there is no oil reserve. Should a storm threaten, the whole turbine could be lowered below the water surface.
Offshore towers and foundations are expensive – Because the turbine floats, no foundation is required on the sea floor, and that allows for a huge reduction in costs. The VAWT would be built on shore, then towed to a field of mooring anchors, tied up, and plugged in. WPE